Flap seal for gas turbine engine movable nozzle flap

ABSTRACT

A gas turbine engine nozzle includes a flap movable relative to a structure. A seal assembly is supported by one of the structure and the flap and includes a seal hinged about an axis. The seal has a sealing profile engaging a seal land of the other of the structure and the flap. A biasing member is configured to urge the hinged seal toward the seal land. A method of sealing a nozzle flap includes supporting a seal relative to a structure along an axis. The seal is urged toward a nozzle flap. The seal rotates about the axis to maintain engagement between the seal and the nozzle flap in response to the urging step.

BACKGROUND

This disclosure relates to a gas turbine engine nozzle. In particular, the disclosure relates to a flap seal for a movable nozzle flap.

Typically, a turbojet engine utilizes a nozzle with movable flaps after its augmenter section. Seals are arranged within the nozzle to seal the flaps relative to adjacent support structure throughout the flap's range of motion.

A unitary metallic member having a V-shaped cross-section is used for one type of conventional seal. The rigid seal provides a pair of legs converging to an apex. The first leg is supported by a structure, and the second leg seals against the flap. The legs form a cavity. Pressure within the cavity of the flap seal urges the second leg into engagement with the structure and flap. The flexible legs of the seal also accommodate assembly tolerances within the nozzle.

SUMMARY

A gas turbine engine nozzle includes a flap movable relative to a structure. A seal assembly is supported by one of the structures and the flap and includes a seal hinged about an axis. The seal has a sealing profile engaging a seal land of the other structure and the flap. A biasing member is configured to urge the hinged seal toward the seal land. In this manner, the sealing function and assembly tolerance function of the seal assembly are decoupled from one another.

A method of sealing a nozzle flap includes supporting a seal relative to a structure along an axis. The seal is urged toward a nozzle flap. The seal rotates about the axis to maintain engagement between the seal and the nozzle flap in response to the urging step.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a schematic view of an example turbojet engine having a nozzle with movable flaps.

FIG. 2 is a perspective view of a structure configured to support a movable flap.

FIG. 3 is a rear view of the structure shown in FIG. 2 illustrating a seal assembly.

FIG. 4 is a cross-sectional view of the structure taken along line 4-4 in FIG. 3.

FIG. 5 is a perspective view of one example biasing member.

FIG. 6 is a perspective view of an example hinged seal.

FIG. 7 is a cross-sectional view of another seal assembly.

FIG. 8 is a cross-sectional view of yet another example seal assembly.

FIG. 9 is a rear view of the seal assembly illustrated in FIG. 8.

DETAILED DESCRIPTION

A gas turbine engine 10, such as a turbojet with an augmenter section 12, is illustrated in FIG. 1. A nozzle 14 is arranged at an exit of the augmenter 12. The nozzle 14 includes a structure 16 supporting movable flaps 18. The movable flaps 18 open and close between multiple positions about a longitudinal axis A to change the nozzle's exit area during operation of the turbojet engine.

Referring to FIGS. 2 and 3, the structure 16 includes a hood 20 that is static or fixed. The hood 20 supports a seal assembly 22 constructed of multiple lateral segments. The seal assembly 22 includes a seal holder 24, secured to the hood 22 by fastening elements 28, 29, and a seal 26. The multiple components of the seal assembly 22 greatly reduce stress on seal 26, which is permitted to pivot relatively freely relative to the hood 20. In the example, the fastening elements 28, 29, correspond to bolts and rivets respectively. The rivets 29 extend through corresponding holes 31 in the structure 16.

The seal holder 24 provides a first hinge portion 30, and the seal 26 includes a second hinge portion 32 that is pivotally supported by the seal holder 24. Only a small portion of the first hinge portion 30 is shown in FIG. 3 for clarity. The first and second hinge portions 30, 32 are arranged laterally adjacent to one another. As shown in FIG. 3, a gap 37 is provided between the first and second hinge portions 30, 32. A biasing member 36 is provided between the first and second hinge portions 30, 32 in the gap 37. Referring to FIG. 4, a pin 42 secures the first and second hinge portions 30, 32 to one another and provides an axis 44 about which the seal 26 pivots in an arc 38.

The seal 26 includes first and second ends 33, 35 that respectively provide the second hinge portion 32 and a sealing profile 34. In the example shown in FIG. 4, the sealing profile 34, which may be provided by a folded portion 46, is linear for engaging a flap 18 having a flat seal land or surface. In one example, the biasing member 36 is a torsion spring, as shown in FIG. 5. The torsion spring includes a coil 50 disposed over the pin 42 and located laterally within the gap (FIG. 3). The coil 50 includes first and second spring legs 52, 54 respectively engaging the seal holder 24 and the seal 26 to urge the seal 26 toward the flap 18.

In operation, a fluid F exits the nozzle 14 past the flaps 18. Another fluid is provided between the flap 18 and the structure 16 to provide a pressure P on the backside of the seal 26, which tends to rotate the seal 26 about the pin 42 toward the flap 18. This pressure P along with the force from the biasing member 36 maintains a seal between the seal 26 and the seal land 40. The hinged seal 26 can also more easily accommodate assembly tolerances by permitting the seal 26 to rotate about the pin 42 toward the seal holder 24. The disclosed configuration is able to accommodate larger deflections than rigid style seals.

Another example seal 126 is shown in FIG. 6. The seal 26 includes a second hinge portion 132 and a curved sealing profile 56, which is suitable for sealing against curved seal lands.

Another seal assembly 122 is depicted in FIG. 7. The seal assembly 122 includes a seal 126 engaging the flap 18. This assembly utilizes an alternate biasing member. The biasing member 136 is a finger spring that includes a first end 58 supported between the hood 20 and the seal holder 24. A second end 60 extends from the first end 58 and engages the seal 126 to urge the seal 126 toward the flap 18.

Another type of finger spring 236 is shown in FIGS. 8 and 9. The finger spring 236 includes first and second ends 62, 64 joined by an intermediate portion 66 that is supported by the pin 42. The intermediate portion 66 is arranged in the gap 37 and located laterally between the first and second hinge portions 30, 32. The first leg 62 engages the seal holder 24, and the second end 64 engages the seal 26.

Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content. 

1. A gas turbine engine nozzle comprising: a structure; a flap movable relative to the structure; a seal assembly supported by one of the structure and the flap and including a seal hinged about an axis and having a sealing profile engaging a seal land of the other of the structure and the flap; and a biasing member configured to urge the hinged seal toward the seal land.
 2. The gas turbine engine nozzle according to claim 1, wherein the structure is a static hood.
 3. The gas turbine engine nozzle according to claim 1, wherein the flap has first and second nozzle positions.
 4. The gas turbine engine nozzle according to claim 1, wherein the seal assembly includes a seal holder secured to the structure by fastening elements.
 5. The gas turbine engine nozzle according to claim 4, wherein the fastening elements is at least one of a rivet and a bolt.
 6. The gas turbine engine nozzle according to claim 4, wherein the seal includes first and second opposing ends, the first end pivotally secured to the seal holder, and the second end providing a seal profile engaging the flap.
 7. The gas turbine engine nozzle according to claim 6, wherein the seal profile is linear.
 8. The gas turbine engine nozzle according to claim 6, wherein the seal is pivotally secured to the seal holder by a pin providing the axis, and the biasing member is supported by the pin and arranged laterally between the seal holder and the seal.
 9. The gas turbine engine nozzle according to claim 8, wherein the biasing member is a torsion spring.
 10. The gas turbine engine nozzle according to claim 8, wherein the biasing member is a finger spring.
 11. The gas turbine engine nozzle according to claim 10, wherein the finger spring includes first and second ends, the finger spring first end supported by one of the structure and the seal holder and the finger spring second end engages the seal and is movable relative to the finger spring first end.
 12. The gas turbine engine nozzle according to claim 10, wherein the finger spring is generally V-shaped providing first and second legs joined by an intermediate portion, the intermediate portion supported by the pin, the first leg engaging one of the structure and the seal holder, and the second leg engaging the seal.
 13. A method of sealing a nozzle flap comprising the steps of: supporting a seal relative to a structure along an axis; urging the seal toward a nozzle flap; and rotating the seal about the axis to maintain engagement between the seal and the nozzle flap in response to the urging step.
 14. The method according to claim 13, wherein the urging step includes applying a fluid pressure to the seal.
 15. The method according to claim 13, wherein the urging step includes biasing the seal with a spring element. 